Cosmetic dentistry
In dentistry, patients’ enthusiasm for their dental aesthetics has grown exponentially in recent decades, aided in this sense by the dictates of the media and other vectors of ideals of all kinds. Dentistry, across all its disciplines, has constantly responded to this expectation, with more or less advanced technical and clinical means but always concerned with the result. This is how the notion of “aesthetic and cosmetic dentistry” appeared.
In dentistry, patients’ enthusiasm for their dental aesthetics has grown exponentially in recent decades, aided in this sense by the dictates of the media and other vectors of ideals of all kinds.
Dentistry, through all its disciplines, has constantly responded to this expectation, with more or less advanced technical and clinical means but always concerned with the result.
- This is how the concept of “ aesthetic and cosmetic dentistry ” appeared.
Aesthetics
The word aesthetics is derived from a Greek noun meaning sensation. Aesthetics etymologically defines the science of the sensible.
- Aesthetics is “the theory, not of beauty itself, but of the judgment which claims to evaluate with justice beauty, as well as ugliness”
Definitions
Cosmetic dentistry
In the introduction to his Aesthetic Guide (Paris and Faucher, 2003) Faucher defines cosmetics by
“art of beautification”
Cosmetic dentistry therefore includes all the care undertaken to improve the attractiveness of a smile, without necessarily improving dental function.
Cosmetic dentistry therefore includes all the care undertaken to improve the attractiveness of a smile, without necessarily improving dental function, whereas aesthetic dentistry incorporates biological considerations and measures to achieve the ideal form, function and appearance.
Cosmetic dentistry is therefore a specific practice whose methods are only related to aesthetics (Savard et al., 2007). Aesthetics conceived as a science of beauty interests all areas of dentistry: conservative dentistry, orthodontics, prosthetics, periodontics, implantology, etc.
- The 20th century saw great advances in technology and health and allowed the rise of dental aesthetics in the 1980s and 1990s. With the emergence of new needs, aesthetics must now be considered as a global therapy, with anamnesis, diagnosis and a specific treatment plan to restore a functional, natural and lasting smile with the aim of bringing the patient to a “state of physical, mental and social well-being”. (Tirlet, 2004) Aesthetics has also become a field of research and a specific practice inseparable from dentistry.
This development leads practitioners to question their practice, particularly with regard to the aesthetic standards of the smile. It is important to ask whether the standardization of the smile is in accordance with the ethical principles and the health mission of the dental practitioner, and what its limits are.
Cosmetic dentistry
Natural oral aesthetics
The techniques of aesthetic dentistry can only be fully mastered if the clinician and the technician are truly familiar with the basic principles of natural oral aesthetics.
Fundamental Aesthetic Criteria:
The Ideal Smile
Criterion 1: Gingival health
Basic components of healthy gums:
-free gingiva (GL): pinkish color, with a matte surface – gingival sulcus (white dotted line),
- Attached gingiva (AG): Pinkish coral color and firm texture (keratinized and attached to the underlying alveolar bone) with an “orange peel” appearance in 30–40% of adults.
Mucogingival junction (black dotted line) and alveolar mucosa (AM): mobile and dark red in color
Criterion 2: closure of the gingival embrasure
In young adults with healthy gingiva, the interdental spaces are closed by the festoon of tissues forming the papillae.
Temporary neglect of oral hygiene and periodontal disease can modify this gingival architecture (i.e. cause the disappearance of the interdental papillae: The uninhabited embrasures or black holes represent an aesthetic disgrace that is difficult to remedy.
Criterion 3: dental axes
The axis of the teeth is inclined from mesial to distal in the inciso-apical direction. This inclination seems to increase from the central incisors to the canines.
Variations in dental axes and midline are common, which does not necessarily call into question the final aesthetic result.
Criterion 5: balance of gingival festoons
The gingival scallop of the lateral incisors is slightly more coronal than that of the central incisors and canines. This ideal situation represents the Class 1 gingival level.
Criterion 6: the level of interdental contact
The situation of interdental contact depends on the position and morphology of the teeth.
It is most coronal between the maxillary central incisors. It tends to be increasingly apical from the anterior teeth towards the posterior teeth.
Criterion 7: Relative dimensions of the teeth
Due to individual variations in proximal/incisal wear, it is difficult to rely on “magic numbers” to define correct tooth dimensions.
It appears that the overall dimensions of the teeth are not related to the size of the subject. The maxillary anterior teeth are wider and longer in men than in women. The ratio of width to crown length has proven to be the most stable reference, since it shows little variation according to sex or between the teeth themselves.
A brighter tooth will appear larger and closer to the observer than a darker tooth.
The results of Sterrett et al., together with other findings, lead to the statement of the following averages for maxillary anterior teeth:
• The coronal width/length ratios of the incisors and canines are identical (between 77% and 86%).
Cosmetic dentistry
Criterion 8: Basic elements of dental form
The central and lateral incisors are intended for tearing and cutting, which explains their anatomical and functional similarities. Their characteristics are as follows:
- straight mesial face, straight,
- slightly rounded incisal angle,
- curved distal face.
- Disto-incisal angles are more open than mesio-incisal angles.
- The free edge of the crown may be irregular or rounded, but often becomes sharper and straighter with functional wear.
The typology of the incisor is also explained by the anatomy of the interproximal ridges, also called transition lines, which represent reflective surfaces determining the perception of form.
Several theories have been put forward to define the optimal dental shape and dimensions, in the absence of objective data:
- Temperament theory developed by Hippocrates: Defined several temperaments: sanguine, bilious, melancholic and phlegmatic. The teeth must take on the appearance and morphology characteristic of these models.
For example :
○ a curvilinear profile would correspond to curved teeth,
○ a flat profile with flat teeth
In 1914, Leon Williams developed a new, more effective geometric theory. It states that the shape of the central incisor corresponds to that of the face, reduced and inverted. It describes four types of faces and teeth: square, triangular, ovoid and mixed (square-triangular).
- Square: straight outline with marked, parallel transition lines and lobes.
- Ovoid: rounded outline with soft transition lines (few lobes) and converging at the incisor and neck (“barrel” shape).
- Triangular: straight outline with transition lines and marked lobes converging at the neck (marked inclination of the distal outline).
Criterion 9: Tooth characterizationCharacterization involves the phenomena of light reflection/transmission (opalescence, transparency, translucency) as well as intense colorations (stains, fissures, dentin lobes, areas of infiltrated dentin) and morphological details (attrition, abrasion). These distinctive elements determine the age and personality of a tooth.
- Opalescence is an optical property of enamel and refers to the ability to transmit certain wavelengths of natural light (red-orange tones) and reflect others (blue-violet tones).
- Translucency defines the nuances that occur between complete opacity (like ivory) and total transparency (like glass).29 Teeth, and especially incisal edges, show intense characteristics incorporating a wide variety of effects defined by translucency and transparency.
Cosmetic dentistry
Criterion 10: surface condition
The determining elements of the vestibular surface condition of the teeth are essentially horizontal and vertical.
The horizontal component is the direct result of growth lines (Retzius striae) which leave fine horizontal stripes on the surface of the enamel, also called perikematia.
The vertical component is defined by the superficial segmentation of the tooth into distinct lobes
Criterion 11: Color
Color is the result of four elements:
- the basic shade: brown, yellow, blue-gray, orange-pink;
- brightness (or luminance or brilliance) which translates the quantity of black or white, and is expressed by the adjectives “light” or “dark”;
- saturation which represents the quantity of tint per unit of surface and therefore its dilution. We say, for example, that a tooth is more saturated at the neck than at the middle third;
- translucency which is the ability of a body to allow light to pass through it. It is located at the free edges and proximal contours.
There are other physical phenomena that can change color:
- Fluorescence : this is the ability to absorb light energy (invisible spectrum, UV, sun) and to quickly restore it in the form of visible fluorescent light.
The fluorescence must be reproduced in a similar way to that on natural teeth in order to optimize the aesthetic rendering.
- Opalescence is the optical property of a transparent or translucent material that gives it a milky appearance or tint, with iridescent reflections reminiscent of those of opal (mineral stone). It is also the ability of a material to appear bluish in reflected light and orange in transmitted light.
- Metamerism: is often presented as the phenomenon by which two surfaces, appearing the same color under a certain light or illuminant, and can appear different colors under another light. Proper lighting is necessary to avoid this phenomenon.
Criterion 12: the configuration of the incisal edges
There are three components to consider.
General shape: In an adult or middle-aged patient, the outline of the incisal edges is often straight or forms an inverted curve which gives a uniform and personalityless smile. In the young patient, the free incisal edges have a characteristic shape due to the relative dimensions of the teeth.
Interincisal angles: The mesio- and disto-incisal angles have a great influence on the definition of the so-called negative space, that is, the background between the maxillary and mandibular teeth when laughing or when the mouth is open.
Thickness Pleasing incisors have a thin, delicate edge. Thick incisal edges can make teeth appear old, artificial, and bulging.
Criterion 13: The lower lip line
The lateral incisors remain at a distance of 0.5 to 1.5 mm from the lip, while the incisors
central and canines are closely related to the lip line.
The coincidence of the incisal edges with the lower lip is essential for a graceful smile. The proximal contacts, the free edges of the teeth and the lower lip are on parallel lines, which is indicative of a harmonious situation.
Criterion 14: Symmetry of the smile
Smile symmetry refers to a relatively symmetrical position of the labial commissures in the vertical plane, deriving directly from the bipupillary line. This is a prerequisite for the aesthetic evaluation of the smile.
Therapeutic options in cosmetic dentistry:
From examination to diagnosis in cosmetic dentistry:
Patients have become more demanding and are less likely to accept any restoration without critical judgment . They want to discuss the treatment plan and participate in its development.
- These are the different techniques to be indicated depending on the request, the analysis and the dental decay.
- The “therapeutic gradient” is an approach to aesthetic treatments, developed by TIRLET and ATTAL. They observed an evolution of patient demands associated with an explosion of techniques and materials that can meet them.
Cosmetic dentistry
The different therapeutic options
Cosmetic dentistry procedures follow a ” therapeutic gradient ” developed by TIRLET and ATTAL, which can be classified on a horizontal axis, from the least mutilating to the most damaging, which takes into account two fundamental factors: time and tissue preservation .
Orthodontics
On the scale of the Therapeutic Gradient, orthodontics is the first of the techniques considered. It allows a restoration of the harmony of the smile, of the physiology and of the function of the stomatognathic system without affecting the vital potential of the dental organ itself.
Adult orthodontics has the following objectives:
- Improve aesthetics:
In case of dental malpositions, orthodontics is the technique of choice to satisfy patients.
Thanks to CAD/CAM, we use invisible and custom-made devices.
- Contribute to prosthetic realization: Orthodontics can facilitate the realization of prosthetic rehabilitations, more aesthetic, more functional and more reliable. We can carry out: realignments, straightening of prosthetic pillars , closing of diastemas, corrections of occlusal curves, lifting of significant overbites, etc.
- Achieving functional occlusion:
The physiological occlusion sought in adults is that which corresponds to a harmonious state of mutual tolerance of the different constituents of the masticatory system, accepting some variations in relation to the ideal occlusion.
Periodontal surgery
Periodontal treatment alone can meet the demand when gingival exposure is not severe.
Periodontal plastic surgery of the gummy smile consists of a crown elongation, that is, the lengthening of the clinical crown, which can be performed in different ways: an internal bevel gingivectomy (IBG), with or without bone resection and an apically positioned flap (APF), with or without bone resection .
The extent of periodontal correction for the treatment of a gummy smile depends on the patient’s gingival exposure at rest and when smiling.
Teeth whitening
Bleaching techniques can be effective in lightening the color of teeth affected by fluorosis, tetracycline administration, and acquired superficial discoloration. Chemical bleaching is the aesthetic treatment of choice, which can be followed later, when necessary, by composite resin bonding or placement of a composite or ceramic veneer.
Microabrasion
Enamel microabrasion is a complementary technique to lightening techniques.
It is a physical and chemical treatment designed to remove the most superficial part of the tooth enamel. This technique is mainly used in the case of demineralization of the enamel causing stains and/or streaks that can range from white to brown, most often in cases of fluorosis.
Mega abrasion
In some cases, it is necessary to resort to what is called mega abrasion or ameloplasty, using fine-grain diamond instruments mounted on a turbine or an ultrasonic handpiece. This action must remain limited, otherwise the initial morphology of the tooth will be considerably modified.
It is sometimes necessary to recreate the micro geography of the vestibular surface, particularly in young patients where the texture of the tooth is particularly rich.
Porcelain veneers
These are thin shells made from strong dental porcelain, which are attached to the visible surface of the teeth. This versatile aesthetic solution can correct several smile defects, including:
- Chipped or broken teeth
- Stains or discolorations
- Irregularly shaped teeth
- Spaces between teeth
- Worn or uneven teeth
- Misaligned or crooked teeth
Dental composite restorations
Faced with growing aesthetic demand from patients, the use of dental composites has grown and improved considerably in recent years. New families have appeared, others have disappeared.
Composite resin is mercury-free, low heat conduction and has adhesive properties. Dental techniques have become less mutilating and more respectful of dental tissues.
Aesthetic ceramic restorations
“The restoration of the natural appearance of a smile cannot be conceived without the use of all-ceramic systems” John MacLean 1975.
- Since the early 1980s, ceramic-ceramic systems have continued to evolve. They are gradually replacing metal-ceramic restorations. This type of restoration must ensure long-term mechanical resistance, biocompatibility and a natural appearance.
Cosmetic dentistry
To restore aesthetics, the practitioner will most often suggest:
– Veneers glued to enamel only (mini veneer and veneer)
– Partial restorations covering enamel and dentin (veneer)
– All-ceramic crown on a tooth with little discoloration
– All-ceramic crown on highly colored dentin
The all-ceramic crown stage is the final step on the TIRLET and ATTAL therapeutic gradient scale.
The advantages of ceramic restorations can also be real obstacles to the survival rates of prosthetic rehabilitation if the operator does not correctly master the preparation and bonding techniques.
Conclusion
The search for aesthetics in dentistry is first of all dependent on the dentist’s sense of observation.
The study of natural teeth, knowledge and understanding of the physical phenomena that govern the circulation of light have given access to a modern dimension of conservative dental medicine: biomimetics.
This discipline not only contributes to the development of the materials themselves, it also aims to integrate existing materials into a rational approach that includes biology, biomechanics and aesthetics.